Two Ni/Co-substituted sandwich-type germanomolybdates based on an unprecedented trivacant polyanion [α-GeMo10O36]8

Two Ni/Co-substituted sandwich-type germanomolybdates, {[M₃(NH₂-trz)₆(H₂O)₆][M₄(H₂O)₂(HGeMo₁₀O₃₆)₂]}·nH₂O (M = Ni²⁺ (1) and Co²⁺ (2), n = 10 (1) or 11 (2), NH₂-trz = 4-amino-1,2,4-triazole), have been obtained under hydrothermal conditions. 1 and 2 represent the first trivacant Keggin germanomolybdates involving unprecedented [α-GeMo₁₀O₃₆]^8- fragments and {M₃O₄} quasi-cubane building units. Both of them exhibit electrocatalytic behaviours for H₂O₂ reduction and photocatalytic properties for CO₂ conversion.

Syntheses, Structures, and Electrochemical Properties of Three New Acetate-Functionalized Zirconium-Substituted Germanotungstates: From Dimer to Tetramer

Under hydrothermal conditions, three new acetate-functionalized zirconium-substituted polyoxometalates, H₄Na₂[Na₆(H₂O)₂₂][Zr₄(μ₃-O)₂(OH)₂(OAc)₂(α-GeW₁₀O₃₇)₂]·32H₂O (1), H₈K₃Na₅[Zr₆(μ₃-O)₃(OH)₃(OAc)(H₂O)(β-GeW₁₀O₃₇)₃]·20H₂O (2), H₆K₄Na₁₂[{Zr₅(μ₃-OH)₄(OH)₂}@{Zr₂(OAc)₂(α-GeW₁₀O₃₈)₂}₂]·22H₂O (3), were synthesized and characterized. In 1, the sandwiched dimer [Zr₄(μ₃-O)₂(OH)₂(OAc)₂(α-GeW₁₀O₃₇)₂]^12- was linked to a hexameric [Na₆(H₂O)₂₂]⁶⁺ cluster to form a 1D chain. In 2, the trimer was constructed from three [β₂-GeW₁₀O₃₇]^10- units and a new [Zr₆O₃(OH)₃(OAc)(H₂O)]¹⁴⁺ cluster. In 3, the tetramer was built by two novel sandwich-type dimers [Zr₂(OAc)₂(α₂-GeW₁₀O₃₈)₂]^18- and one unique [Zr₅(μ₃-OH)₄(OH)₂]¹⁴⁺ core in an approximately orthogonal fashion, showing a staggered tetrahedral polyanion. Also, the electrochemistry and electrocatalytic properties of 3 were studied, exhibiting good catalytic activities toward the reduction of H₂O₂, BrO₃^-, and NO₂^-.

Organic–inorganic hybrids assembled from plenary Keggin-type germanotungstate units and 3d–4f heterometal clusters

Two kinds of 3d–4f heterometal plenary Keggin germanotungstates were prepared. Their electrochemical sensing properties towards Acetaminophen detection were investigated.

Two rare Cr–Ln (Ln = Dy, Tb) heterometallic cluster substituted polyoxometalates featuring hexameric aggregates: hydrothermal syntheses, crystal structures and magnetic studies

Two hexameric Cr–Ln cluster substituted POMs have been obtained under hydrothermal conditions. They represent the first examples of 3d–4f heterometallic cluster substituted POMs incorporating Cr–Ln clusters.

Large Magnetic Polyoxometalates Containing the Cobalt Cubane '[CoIIICo 3II (OH)3(H2O)6-m(PW9O34)]3-' (m = 3 or 5) as a Subunit

A synthetic procedure is presented to construct new magnetic polyoxometalates (POMs) containing one or two subunits of ‘[Co^IIICo3II(OH)₃(H₂O)_6−m(PW₉O₃₄)]³⁻' (m = 3 or 5). The substitution of the water ligands present in these subunits by oxo or hydroxo ligands belonging to other POM fragments, gives rise to four, larger POM anions: [Co₇(OH)₆(H₂O)₆(PW₉O₃₄)₂]⁹⁻ (2), [Co₇(OH)₆(H₂O)₄(PW₉O₃₄)₂]n9n- (2′), [Co₁₁(OH)₅(H₂O)₅(W₆O₂₄)(PW₉O₃₄)₃]²²⁻ (3) and [{Co₄(OH)₃(H₂O)(PW₉O₃₄)}₂{K⊂(H₂W₁₂O₄₁)₂}{Co(H₂O)₄}₂]¹⁷⁻ (4). The crystal structures, magnetic characterization and stabilities in aqueous solutions of these POM derivatives are also presented.

Lanthanoid Template Isolation of the α-1,5 Isomer of Dicobalt(II)-Substituted Keggin Type Phosphotungstates: Syntheses, Characterization, and Magnetic Properties

A new series of heterometallic 3d-4f sandwich type phosphotungstates, [Ln{PCo2W10O38(H2O)2}2](11-) (Ln = Sm(III), Eu(III), Gd(III), Tb(III), Dy(III), Ho(III), Er(III), Tm(III), Yb(III), and Lu(III), denoted 1a-10a, respectively), have been synthesized by a one-pot reaction procedure on reacting the dilacunary K14[P2W19O69(H2O)]·24H2O precursor with Ln(NO3)3·nH2O and Co(NO3)2·6H2O in an aqueous potassium chloride solution. All the compounds were isolated as potassium salts and further characterized with different analytical techniques such as single-crystal X-ray diffraction, Fourier transform infrared spectroscopy, high-resolution electrospray ionization mass spectrometry, elemental analysis by inductively coupled plasma atomic emission spectroscopy, magnetic measurement, and thermogravimetric analysis. Single-crystal X-ray diffraction analysis of the compounds reveals that all these compounds are isostructural and crystallized in the orthorhombic crystal system in space group Iba2. The polyanions contain the α-1,5 isomer of dicobalt-substituted α-Keggin phosphotungstate, which sandwiched lanthanoid cation and formed novel heterometallic dimer species. The temperature-dependent magnetic susceptibilities of 1a, 2a, 4a, and 7a-10a indicate the dominant contribution of the ferromagnetic interaction between Co(II) and Co(II) within the cluster, while the antiferromagnetic interaction between Co(II) and Ln(III) dominates for 3a, 5a, and 6a. The isothermal magnetizations of 1a-10a show a gradual increase in magnetization at low fields and do not reach saturation even at 50 kOe.

A heterometallic (Fe6Na8) cage-like silsesquioxane: synthesis, structure, spin glass behavior and high catalytic activity

The exotic “Asian Lantern” heterometallic cage silsesquioxane [(PhSiO_1.5)₂₀(FeO_1.5)₆(NaO_0.5)₈(n-BuOH)_9.6(C₇H₈)] (I) was obtained and characterized by X-ray diffraction, EXAFS, topological analyses and DFT calculation.

First quadruple-glycine bridging mono-lanthanide-substituted borotungstate hybrids

A class of novel organic–inorganic hybrid quadruple-glycine lanthanide-substituted Keggin-type borotungstates have been synthesized and characterized.

Research progress on polyoxometalate-based transition-metal–rare-earth heterometallic derived materials: synthetic strategies, structural overview and functional applications

This review summarizes the structural types of reported polyoxometalate-based transition-metal–rare-earth heterometallic derived materials (PTRHDMs) together with synthetic strategies, structural motifs and relevant functional applications.

Two types of novel tetra-iron substituted sandwich-type arsenotungastates with supporting lanthanide pendants

Two classes of novel tetra-iron substituted sandwich-type arsenotungastates with supporting lanthanide pendants have been synthesized and characterized.